The corrosion resistance of tantalum metal against metal melts

Tantalum is a sensible choice whenever high corrosion resistance is required. Even though tantalum is not one of the noble metals, it is comparable to them in terms of chemical resistance. When exposed to air, tantalum forms a very dense oxide layer (Ta2O5) which protects the base material from aggression. This oxide layer therefore makes tantalum corrosion-resistant.

Tantalum is resistant to a series of metal melts such as Ag, Bi, Cd, Cs, Cu, Ga, Hg, K, Li, Mg, Na and Pb, provided that these melts have a low oxygen content. However, the material is affected by Al, Fe, Be, Ni and Co.

Tantalum metal: Corrosion resistance against metal melts

Aluminum (AL)

not resistant

Lithium (Li)

resistant at < 1000 °C

Beryllium (Be)

not resistant

Magnesium (Mg)

resistant at < 1 150 °C

Lead (Pb)

resistant at < 1000 °C

Sodium (Na)

resistant at < 1000 °C

Cadmium (Ca)

resistant at < 500 °C

Nickel (Ni)

not resistant

Caesium (Cs)

resistant at < 980 °C

Mercury (Hg)

resistant at < 600 °C

Iron (Fe)

not resistant

Silver (Ag)

resistant at < 1200 °C

Gallium (Ga)

resistant at < 450 °C

Bismuth (Bi)

resistant at < 900 °C

Potassium (K)

resistant at < 1000 °C

Zinc (Zn)

resistant at < 500 °C

Copper (Cu)

resistant at < 1300 °C

Tin (Sn)

resistant at < 260 °C

Cobalt (Co)

not resistant

Chemical reactions arise very quickly when base materials such as tantalum are brought into contact with noble materials such as platinum. You should therefore take careful account of the behavior of tantalum in contact with other materials present in the system, especially when working at high temperatures.